Water Gardens: Pond pumps?

Here's my raised,long concrete pond, just built, painted with a pond sealent and has 8 goldfish in it just to start with.
I'm wondering what sort of pump and filtration i'd need on such a long shaped pond?
It's about 5m long, 1.7 wide and about 60cm deep. I plan on having some lily pads, a big fresh water fish of some sort and maybe a small water fall up one end over rocks. No fountain..and most of the pumps i can get are for fountains.
I just don't want to change the water often and im wondering how good the water will circulate but will a to strough a pump blow the water out?
Anyone have a pond like this?

I'm the queen of weirdo ponds, and weirdo pond shapes... If you didnt put any plumbing while building it, then the next best bet would be a submersible pump with an outside canister filter. Both can be found for a reasonable price on eBay. Get the filter that has a UV light, to keep the algae out. Total will be maybe $250. A pump will run you around $98 ON eBay...(2500-3500 gph) and a 2,000 to 3,000 gal canister filter. That way you can handle both fish and plants.

If you are going to have fish you must have plumbing and a pump, and a good filter, preferable with UV light. That waterfall could be your salvation! Build the base form extra stout, and extend it over the lip of your pond about 6 in, what's that about 15cm. Design the house for the pumps with the waterfall on top of it, down on the other end opposite the stairway. That way you could hide the plumbing going into and from the pool beneath it, letting the plumbing run over the lip of the pool and down into the water. I'm afraid I'm too far away to help.
There is a pump made for every conceivable purpose on earth. Take some good advice, pumps are cheaper than fish, buy a backup! I prefer a parallel backup pump with valves, but I spent too long in the oilfield. Do your research on the internet.
Just Google "pond pumps" for a start. Might better make that "Aussie pond pumps".
Design is everything in construction, the pumps won't blow water out because you have to have pipes big enough to circulate that volume of water so the pressure will not be too high. You may need some help designing this thing so you won't have to redo it over and over because you kept using too small a pump and pipes, and killing your fish. That's a big pond, 5.1 cu meters or 1119 British gallons, 1346 US gallons.
I want one too, my, my but that's a pretty cement pond as they say on the Beverly Hillbillies.
Thomas

hi mothermole- its a concrete pond, formed up and poured onsite. Lets just say my partners a builder and he employes a few guys and they were having a quite few days. hehe! Its painted with a bluey-grey pond sealant. The paths were later poured around it. I do have some pics..just gotta find them.

Well i put a stingray pump inside the pond and a big outside canister filter with the uv light and all looks good so far.. have to wait and see now. I could add another pump i supose later. We only have some goldfish in the pond at the moment while were stuffing around with it..don't think you can kill them. hehe!
Once alls good my partners hopeing to get a big fresh water fish of some sort.

Best of luck with your new pond! It seems to me that most ponds will have an algae burst when they are first getting established, or when temps suddenly rise. Your UV filter will help with that. Keep us updated!